Donovan Wright
Woodland Management
Kent is one of the most wooded counties in the South East, with well over 45,000 hectares of woodland, ranging from sweet chestnut coppice and wet woodland to lowland beech and yew woodland.
Many factors determine why a woodland has evolved in a particular manner and what species are present, including geology, soil type, drainage, present and past management, isolation from other woodlands and the presence of browsing animals such as deer.
For centuries, woodlands were intensively managed to provide coppice and timber products such as fencing materials, timber for construction, firewood and food. Contrary to popular belief, most of the woodlands which we know so well today have come about as a result of being heavily managed, and the wildlife which we have come to associate with this particular habitat will gradually disappear if these woodlands are no longer managed.
Traditional woodland management is very labour intensive and big machinery is often used to harvest the trees. This is less than ideal for wildlife. By introducing European bison, an ecosystem engineer, we are encouraging a more natural approach to woodland management. This will create a greater mosaic of habitats which will maximise the opportunities for wildlife to flourish.
Bison naturally manage the woodlands in which they roam in a way that no other animal can. At the Blean,
we need to encourage more light to the woodland floor and increase the amount of deadwood to benefit native plants and animals.
The way bison graze and interact with their surroundings is unique. By eating tree bark rather than targeting other parts of a tree, bison create more standing dead wood.
Dust bathing and creating ‘bull pits’ or ‘sand baths’ to remove parasites creates brilliant habitats for a huge range of insects. Removing moulting fur by rubbing against trees provides nest materials for birds. Importantly, due to their large size and strength, bison are able to create corridors through densely vegetated patches which, in turn, links up microhabitats. All these behaviours can create a healthy life cycle in the woodland and creates gaps in the canopy that provide a 3-dimensional habitat to the benefit of a variety of species. Without animals like bison, these functions would be missing in the Blean, and the Wilder Blean project aims to restore those natural processes.
Other types of Woodland Management
Coppicing
Coppicing is a woodland management process that benefits a wide variety of wildlife. The purpose is to cut the trees down on a rotation (approximately every 15-20 years) which allows light back to the woodland floor and in return will see a huge variety of woodland plants emerging, which will then attract an abundance of insects and birds.
In this specific woodland, the trees are actually much older than 20 years and so the need for coppicing them is much more urgent. The trees that have been cut will not have been harmed by the process and will begin growing again the following spring – the process of coppicing actually significantly increases the life span of these trees. As the trees grow and mature, the light levels to the woodland floor gradually change too, meaning that different plants (that prefer shade) will emerge through the cycle. The changing light levels and cyclical nature of the process makes coppicing an extremely valuable management tool to help a huge variety of wildlife to flourish.
The reason that trees can do this is because they have evolved to cope with being eaten by animals so coppicing is a human activity which mimics what the bison and other animals can do for us in the future.
Thinning
Thinning is the selected cutting down of trees in an area to reduce their density. The aim of thinning is much the same as coppicing in that it allows more light to reach the woodland floor and stimulates new plants to grow. It also has the added benefit of allowing the remaining trees to grow wider and put out new side branches which give more places for species to live.
If you take a look at the oak trees in West Blean, you’ll notice that they are very tall and straight. This is great for producing straight timber for furniture and houses, but not so great for giving wildlife places to live. By removing a certain percentage of these trees, the site will grow richer in wildlife.
The trees that are removed will be put to good use by creating products from the timber. The carbon that they have sucked out of the air is locked up indefinitely and with the remaining trees growing they’ll be capturing even more carbon from the air, helping to fight the climate crisis.
Felling
In the areas that have been planted with non-native conifers (mostly Corsican pine at West Blean), the trees are so dense that we can remove trees a little more quickly. We still can’t remove them all at once as the change would be too great for the wildlife that has managed to survive here, but more are taken out at once to allow more light in and allow the native tree seeds to start germinating.
Unlike broadleaf trees, conifers do not coppice in the same way, so once they are felled the native trees can start to take hold.
As with the oak trees, this timber can go into useful products that lock up carbon.
Pollarding
Structurally diverse woodlands that have a wide range of micro-habitats tend to have more biodiversity. Structural diversity means that there are, for example, trees of different ages (which is not the case in a beech or conifer plantation), but also different physical ‘layers’: leaf litter and soil, ground vegetation, understorey of saplings and shrubs, taller coppice and young trees, and then the woodland canopy.
Micro-habitats include standing and lying deadwood, damp and shady areas, sunny, sheltered glades, scrub, ponds, standards (single stem trees or timber trees as they are sometimes known), veteran trees, pollards and coppice stools.
Research indicates that many species prefer to live in the first ten meters from a woodland edge, where there is more sunlight. Coppicing and creating rides and glades can enhance the biodiversity of a woodland by increasing the levels of light, rejuvenating individual trees and allowing shorter vegetation and shrubs to grow, thus creating more structural diversity and micro-habitats for more species to thrive.
Dormice and other small mammals, and invertebrates like dragonflies, forage for insects along woodland rides. Reptiles bask in the shorter, warmer grassland areas (with scrub and tall grassland for cover nearby). Butterflies and moths will benefit from an increase in wildflowers and grasses, since many species have specific larval foodplant requirements and are reliant on nectar for food. Other species such as bumblebees will also benefit from an increase in nectar and pollen-rich plants.
As long as there is no risk of a tree falling on somebody, leaving a dead or dying tree standing can really benefit woodland wildlife. Dead wood will provide food for hundreds of types of animal, fungus, lichen and moss.
Fungi softens the wood of dead trees through decay, and beetle larvae start chewing it up. In turn, the beetles provide food for woodpeckers, which make nest holes in the rotting wood. Meanwhile, holes that form where old broken branches have decayed provide crevices for bats and birds to roost.